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In networking, connectivity matters just as much as speed and capacity. The easier one can integrate a new component, be it hardware or software, the better life becomes for the network manager..

It makes sense, then, to make network systems as open as possible. Proprietary platforms can be made to work together, but usually at the expense of hefty processing overhead that adds latency and introduces jitter and other artifacts into the data stream. Small wonder that software defined networking (SDN) relies heavily on open systems, considering the highly flexible, dynamic data environments they are intended to support.

Of course, there's open and then there's open. While the software layer of SDN seems open enough by virtue of the OpenFlow protocol, the same can’t be said for the hardware side.

What’s that? Hardware? Isn’t the reason for deploying SDN in the first place to eliminate hardware worries?

Well, yes and no. As I and many others have pointed out, SDN lets you deploy a wide variety of network configurations at the drop of a hat, but all those configurations must still reside on a physical network infrastructure. And when it comes to network interoperability, capital and operational costs, scalability and a host of other factors, physical networks need love, too.

Cisco ONE: Truly open?

Take a look at Cisco’s Open Network Environment (ONE), for example. The company peppers its literature with the word “open." Again, through support of OpenFlow and other industry standards, the system does enable open networking on the virtual layer. But a closer read reveals that key areas, most notably the APIs for third-party application development, are tied to Cisco’s proprietary network operating systems, IOS XR and NX-OS. The upshot is that while Cisco hardware will support open SDN networks, even those that also feature non-Cisco hardware, hardware running Cisco IOS software – like, oh, the Nexus 1000V switch – will optimize management and orchestration. So while ONE does qualify as an open SDN platform, it's kind of like saying that Windows qualifies as an open platform because it accommodates any hardware or software component that's Windows-compatible.

Now, to be fair, Cisco has not tried to hide its contention that it aims to provide an improved SDN experience on its own hardware, and no, this has nothing to do with protecting lucrative revenue streams. However, many open source enthusiasts say that only by opening up the OS level will we achieve the crown jewel of networking: a fully open virtual network architecture residing on low-cost commodity hardware. And as soon as the open source conversation circles around to the OS, someone mentions Linux.

Cumulus Linux and Wind River: Has Linux's time come?

In a little-noticed announcement earlier this year, a company called Cumulus Networks unveiled the Cumulus Linux OS, a networking version of the popular open source PC operating system. The company says Cumulus Linux will provide all the benefits of SDN without the cost of expensive, proprietary network infrastructure. By leveraging bare-metal components from Quanta, Accton, Agema and others, Cumulus Linux promises not only lower capex and opex, but improved network flexibility through common automation and orchestration tools like Puppet and Ganglia. At the same time, the system provides advanced routing between physical and virtual servers, providing additional flexibility when it comes to designing custom network environments.

Meanwhile, Intel – always a fan of commodity hardware markets – has jumped into Linux-based networking as well, tapping the Wind River Open Network Software system for its new Open Network Platform (ONP) reference design. Wind River ONS, based on Wind River’s own Linux distribution, supports both OpenFlow and Open vSwitch, with the added benefit of improved coordination between server and network switching elements for improved security and more broadly extensible network services. Note, however, that the ONP platform is built around Intel’s 6700 series Ethernet processor and the 89xx Communications Chipset, so it remains unclear how well the system will carry across non-Intel hardware.

Regardless, the rise of Linux-based networking is leading some experts to wonder if the OS will finally emerge as a dominant enterprise platform – this time by default. Tech consultant Scott Reeves, for example, notes that Linux’ kernel customization capability makes it ideal for real-time embedded systems, because it allows for stripped-down versions that require only the barest level of support. In this way, Linux can perform very simple functions – like moving bits from here to there – without burdening systems with unnecessary overhead. Brocade in particular seems to have hit on this notion with its Fabric OS release, essentially a version of Linux optimized for real-time switching environments.

Anyone who’s ever worked in open environments knows that open does not necessarily mean plug-and-play. It often requires quite a bit of customization and interoperability testing, as well as other tasks, to ensure that open systems function as intended. And ultimately, even Cisco and VMware users should have no trouble provisioning the network of their dreams given that the ecosystem of compatible resources will extend throughout the cloud.

As for expense, commodity hardware does cost less, but but isn't necessarily the best option. Proprietary networks may come at a premium, but their components are usually ready to go right out of the box. That’s an added value CIOs will have to weigh for themselves.

This article was originally published on Aug 16, 2013

Arthur Cole covers networking and the data center for IT Business Edge. He has served as editor of numerous publications covering everything from audio/video production and distribution, multimedia and the Internet to video gaming.